Positioning of Patient and Needle for Diagnostic Paracentesis Using the Z-tract Technique To perform a paracentesis, place the patient in a supine position with the head of the bed elevated 30° to 45°. Insert the needle at the level of percussable dullness on the abdominal wall. Preferred sites of needle insertion avoid vascular structures and include the midline 2 cm below the umbilicus or the area of flank dullness in the left lower quadrant lateral to the rectus abdominus muscle. For a diagnostic paracentesis, use a 22-gauge needle attached to a 20 to 50 mL syringe. With the nondominant hand, stretch the skin 1 to 2 cm caudad to the point of insertion and maintain tension. Slowly advance the needle while gently aspirating to allow free return of ascitic fluid once the peritoneal space is entered. After collecting sufficient fluid for analysis, remove the needle rapidly and allow the skin to resume its natural position. Place an adhesive bandage over the insertion site. Source: Paracentesis, The Rational Clinical Examination: Evidence-Based Clinical Diagnosis Citation: Simel DL, Rennie D. The Rational Clinical Examination: Evidence-Based Clinical Diagnosis; 2016 Available at: https://jamaevidence.mhmedical.com/DownloadImage.aspx?image=/data/books/845/sim_ch58_f002.png&sec=68733456&BookID=845&ChapterSecID=61357627&imagename= Accessed: December 26, 2017 Copyright © 2017 American Medical Association. All rights reserved